Calf massager: Intervention for body muscle discomfort during prolonged standing

Many occupations require workers to stand for long periods of time without proper interventions, which causes discomfort in the back and lower limbs. Therefore, this study aims to assess the effectiveness in alleviating body muscle discomfort during prolonged standing through the use of a calf massager. This study was conducted among male workers at a manufacturer with production line workers and the list was obtained from the HR Department and simple random sampling was done by number categorization. A total of 100 respondents (50 respondents for both the control and the experimental groups) participated in this study. The experiment took place in a room with a similar setup for the production line. Each respondent was requested to perform the simulated task for 2 hr. For the experimental group, the calf massager was turned on every 15 min. At every 15‐min interval after turning on the calf massager, respondents from both groups were required to evaluate their discomfort level on a Borg's scale CR‐10 questionnaire. The results showed that the level of body discomfort among respondents in the experimental group reduced (20–30%) compared with that of the control group. Multivariate analysis results revealed that the discomfort rating for the lower back, knees, thighs, calves, and feet was significantly lower (p < .05) among the experimental group compared with the control group. For lower body parts, the lower back region was statistically significant (p < .05) at the 90th, 105th, and 120th min; the thigh region was statistically significant (p < .05) at the 120th min; the knee region was statistically significant (p < .05) at the 105th and 120th min; the calf region was statistically significant (p < .05) at all minute intervals except the 15th and 45th min, while the feet region, was statistically significant at the 105th and 120th min. Therefore, this study indicates that calf massage treatment is capable of reducing body muscle discomfort during prolonged standing and highlights the significance of calf massage.     

室内照明统一眩光值(UGR)校准装置的研制

统一眩光值UGR是表征室内照明眩光程度高低和视觉舒适度的重要参数,在室内照明检测和照明设计中有着广泛应用。目前国内对于眩光测试仪的溯源方法一般只采用光亮度标准装置校准亮度值,而对于照明光源的亮度分布和几何位置信息都没有进行相关校准,造成眩光测量结果的失准和不统一。针对此问题,本文研制了一套统一眩光值UGR校准装置,介绍了装置原理和结构,并对其不确定度进行分析。该装置的研制对于保障眩光测量结果的准确统一,有效提升照明设计质量,保护视觉健康有着重要作用。     

Optimal load rating-based inspection planning of corroded steel girders using Markov decision process

Steel girder bridges are vulnerable to corrosion. To maintain their safety above a predefined target level, the load rating can be computed from the inspection results and guide the following maintenance actions. Optimizing inspection and maintenance based on load ratings has substantial practical and economic relevance. Load rating-based strategies can be categorized based on whether the inspection interval and replacement criteria are fixed or flexible. Existing studies focus on fixed inspection intervals throughout the service life. In general, their results are not optimal for inspection planning. To reduce life-cycle cost, aged steel girders may be inspected and repaired in an adaptive manner. To this end, a method based on Markov decision process (MDP) is proposed to compare the life-cycle cost of four load rating-based policies (i.e. uniform or adaptive non-uniform inspection interval, and fixed or adaptive replacement threshold). Load rating-based inspection planning is formulated as MDP and the optimal plans are obtained using dynamic programming. The conventional approach to discretize states cannot accurately approximate the non-stationary deterioration process, while state augmentation is successful in doing this but will increase computational cost. A comparison of two approaches is made to investigate their effects on life-cycle cost. A bridge girder under corrosion attack is used as an illustrative example. The results show that the load rating-based plan with an adaptive non-uniform inspection interval and fixed replacement threshold obtained using the state augmentation technique can be near-optimal.     

一种基于证据推理的视频运动目标融合检测算法

为了解决复杂场景下传统的运动目标检测问题, 利用证据推理—–谨慎有序加权平均方法(COWA-ER), 提出一种综合使用混合高斯、均值滤波和码本的多方法融合的检测方法. 该融合检测算法以上述3 种检测方法为准则建立一个多准则决策框架, 通过双阈值检测法来表征检测过程中的不确定性, 最终利用COWA-ER 方法进行决策级融合, 实现多种方法的优势互补. 实验表明, 所提出的融合检测算法具有更理想的目标检测效果, 能有效应对诸如阴影及光照突变等问题对检测性能的影响.

     

十二五期间电机节能改造、淘汰政策解读

解读、分析十二五期间国家相继出台的关于电机节能的《中小型三相异步电动机能效限定值及能效等级》、《关于组织实施电机能效提升计划(2013~2015年)的通知》、《高耗能落后机电设备(产品)淘汰目录》等一系列政策,并就电机使用单位淘汰旧电机、更新高效节能电机提出建议。     

基于FG-MCGDM的水利工程施工进度方案优化

针对水利工程施工进度的多准则群决策问题,提出了一种新的模糊灰色多准则决策模型。该模型基于模糊集理论、灰色关联分析和折衷解的理论方法,将各决策属性和决策者权重的语言变量转化为梯形模糊数;采用改进的 GRA-VIKOR方法对模糊信息群体决策问题进行求解,并对各决策者的群体效益值和个体遗憾值进行聚合;通过折衷解对施工进度方案进行排序,获得最优方案。该模型有效地避免了信息的扭曲和丢失,确保了决策信息的完备性。通过在某水利工程施工进度方案优选的案例分析与计算,证明了该模型的有效性和实用性。     

Air distribution in room ventilated by fabric air dispersion system

Several researches about airflow distribution in a room generated by fabric air dispersion system (FADS) were reported, but details about the simulation in computer fluid dynamics (CFD) method were not elaborated. In present work The commercial software FLUENT with standard k−ε$k-\epsilon$ turbulence model is applied to predict air distribution in a room ventilated by FADS in penetration mode, where FADS is described with the porous media model based on the modified Forchheimer equation. And more details about the simulation are given. Flow visualization near the region of FADS is conducted using dry-ice as a smoking material. The distribution of indoor air velocity and temperature and draught rating (DR) around the ankle and neck level are predicted. The simulation well matches the corresponding experimental value and results of earlier work. Results showed that air is radially discharged out in the direction perpendicular to the spatial cambered porous fibre in lower velocity, and evenly distributed along its length direction when air is distributed by FADS in penetration mode. The velocity of indoor air is very low, and the vertical air temperature difference is small (less than 2 K). DR around the ankle and neck is immune to supply air flow rate and location, which is less than the comfort limit of ASHRAE Standard 55-2004. In addition, airflow pattern is greatly impacted by the location and strength of heat load.     

座椅下圆柱型多孔送风器的噪声测试和分析

通过对剧院座椅下圆柱型多孔送风器噪声的测试及其结果分析,指出这种送风器的噪声能符合剧院允许噪声标准,可以在剧院空调中应用。     

澳大利亚和新西兰的窗能效评级制度

本文介绍了澳大利亚和新西兰的窗能效评级制度、能效标识等.     

钢结构耐火极限试验研究

文章介绍了钢结构耐火极限试验条件，对裸露钢结构耐火试验、耐火极限与Hp/A的关系进行了分析，对现有钢结构的几种防火保护措施和对应的试验结果比较，探索其它防火保护措施，指出现有防火保护技术存在的问题和需要进一步研究的内容。